import org.w3c.dom.Node;

public class BinaryTree {
    class TreeNode{
        public char val;
        TreeNode left;
        TreeNode right;

        public TreeNode(char val) {
            this.val = val;
        }
    }

    public TreeNode createTree(){
        TreeNode A = new TreeNode('A');
        TreeNode B = new TreeNode('B');
        TreeNode C = new TreeNode('C');
        TreeNode D = new TreeNode('D');
        TreeNode E = new TreeNode('F');
        TreeNode F = new TreeNode('F');
        TreeNode G = new TreeNode('G');
        TreeNode H = new TreeNode('H');
        A.left = B;
        A.right = C;
        B.left = D;
        B.right = E;
        C.left = F;
        C.right = G;
        D.left = H;
        return A;
    }
//    前序遍历
    void preOrder(TreeNode root){
        if (root == null){
            return;
        }
        System.out.print(root.val + " ");
        preOrder(root.left);
        preOrder(root.right);
    }

//    中序遍历
    void inOrder(TreeNode root){
        if (root == null){
            return;
        }
        postOrder(root.left);
        System.out.print(root.val + " ");
        preOrder(root.right);
    }
//    后序遍历
    void postOrder(TreeNode root){
        if (root == null){
            return;
        }
        postOrder(root.left);
        preOrder(root.right);
        System.out.print(root.val + " ");
    }
//    获取树中结点的个数
        int count ;
    int size(TreeNode root){
        if (root == null){
            return 0;
        }
        count++;
        size(root.left);
        size(root.right);
        return count;
    }

    int size2(TreeNode root){
        if (root == null){
            return 0;
        }
        return count = size2(root.right)+size2(root.left)+1;
    }
    public int leafSize;
    public void getLeafNodeCount(TreeNode root){
        if (root == null){
            return;
        }
        if (root.left == null && root.right == null){
            leafSize++;
        }
//        size2(root.left);
//        size2(root.right);
        getLeafNodeCount(root.left);
        getLeafNodeCount(root.right);
    }

    public int getLeafNodeCount2(TreeNode root){
        if (root == null){
            return 0;
        }
        if (root.left == null && root.right == null){
            return 1;
        }
        return getLeafNodeCount2(root.left) + getLeafNodeCount2(root.right);
    }

//    root的第k层有多少个节点
    public int getKLevelNodeCount(TreeNode root,int k){
        if (root == null){
            return 0;
        }
        if (k == 1){
            return 1;
        }
        return getKLevelNodeCount(root.left,k-1) + getKLevelNodeCount(root.right,k-1);
    }

    public int getHeight(TreeNode root){
        if (root == null){
            return  0;
        }
        int lfetHeight = getHeight(root.left);
        int rightHeight = getHeight(root.right);

        return Math.max(lfetHeight,rightHeight)+1;
    }

    public TreeNode find(TreeNode root,int value){
        if (root == null){
            return null;
        }
        if (root.val == value){
            return root;
        }

        TreeNode leftVal = find(root.left,value);
        if (leftVal != null){
            return leftVal;
        }

        TreeNode rightVal = find(root.right,value);
        if (rightVal != null){
            return rightVal;
        }
        return null;
    }
}
